1. Field of the Invention
The present invention relates to a system of a microprocessor suitable for simultaneously executing a plurality of independent programs.
2. Description of the Related Art
As an operation system of the microprocessor suitable for simultaneously executing a plurality of independent programs, an interruption system, a time slice system, and a multiprocessor system have been conventionally used.
The interruption system can be explained as follows.
If a specific interruption signal is generated while a program of a computer is executed, the program that is being executed is suspended and the program is branched to another routine for processing the specific program in which the interruption is received. After the program is executed, the program is returned to the original routine, and the operation of the original program is started again.
The time slice system can be explained as follows:
A plurality of programs are processed in the predetermined order of their priority at a constant time, that is, using time for CPU which a scheduler assigns to the program.
The multiprocessor system can be explained as follows:
A plurality of CPUs are provided and a plurality of programs are processed in parallel, in order to realize the computer system having high performance, which is excellent in high speed, reliability, and expandability.
However, in the microprocessor of the interruption processing system, the following problem exists.
While the program is branching to another routine for processing the specific program, other programs must be interrupted. Due to this, loss time is generated, and execution speed of the microprocessor is reduced.
In the microprocessor of the time slicing system, the following problem exists.
Since using time for a CPU, which a scheduler assigns to the program, is roughly sliced (ms unit), time restriction must be received.
In the microprocessor of the multiprocessor system, the following problem exists.
Since a plurality of CPUs of parallel processing type are needed, the manufacturing cost increases, the management of the CPUs are complicated, and the efficiency of CPUs are generally decreased.